Methods and apparatuses for shifting data signals to match command signal delay

ABSTRACT

Methods and apparatuses for shifting data signals are disclosed herein. An apparatus may comprise a clock generation circuit, a delay path, and a driver. The clock generation circuit may be configured to receive an input clock signal and generate a plurality of clock signals based, at least in part, on the clock signal. A delay path may be coupled to the clock generation circuit and configured to receive the input clock signal and the plurality of clock signals. The delay path may be further configured to receive a data signal and delay the data signal based, at least in part, on the input clock signal and each of the plurality of clock signals. A driver may be coupled to the delay path and configured to receive the delayed data signal, and may further be configured to provide the delayed data signal to a bus.

TECHNICAL FIELD

Embodiments of the present invention described herein relate generally to memories, and more particularly, in one or more of the illustrated embodiments, to shifting data signals, for example, in memory systems.

BACKGROUND OF THE INVENTION

In semiconductor memory, proper operation of the memory is based on the correct timing of various internal command, data, and clock signals. For example, in writing data to memory internal clock signals that clock data path circuitry to latch write data may need to be provided with specific timing relationships with internal write command signals to properly enable the data path circuitry to provide the latched write data for writing to memory. If the timing of the internal write command signal is not such that the data path circuitry is enabled at the time the internal clock signal clocks the data path circuitry to provide the write data at an expected time, the write command may be inadvertently ignored or the write data provided to the memory may not be correct (e.g., the write data is associated with another command).

Thus, internal clock, data, and write command paths should be designed to provide propagation delays for the respective signals to account for latency, for example, write latency between receipt of a write command and receipt of the write data for the write command. Other examples of commands that may require the correct timing of internal clock, data, and command signals for proper operation include, for example, read commands and on-die termination enable commands.

An example conventional approach to maintaining the timing of internal write command, data, and clock signals is modeling both the clock and data path, and the write command path to have the same propagation delay using, for instance, a plurality of logic gates, such as inverters or buffers. Because logic gates may add a relative small amount of delay, the number of gates used may often be higher than desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an apparatus according to an embodiment of the invention.

FIG. 2 is a block diagram of a delay path that may be used in the apparatus of

FIG. 1 according to an embodiment of the invention.

FIG. 3 is a block diagram of a delay path that may be used in the apparatus of

FIG. 1 according to an embodiment of the invention.

FIG. 4 is a timing diagram of an operation of the apparatus of FIG. 1 according to an embodiment of the invention.

FIG. 5 is a schematic diagram of a latch that may be used in the apparatus of

FIG. 3 according to an embodiment of the invention.

FIG. 6 is a block diagram of a memory that may include the apparatus of FIG. 1 according to an embodiment of the invention.

DETAILED DESCRIPTION

Methods and apparatuses for shifting data signals are disclosed herein. In accordance with one or more embodiments of the present invention, data may be shifted through a delay path based, at least in part, on one or more clock signals. Certain details are set forth below to provide a sufficient understanding of embodiments of the invention. However, it will be clear to one having skill in the art that embodiments of the invention may be practiced without these particular details. Moreover, the particular embodiments of the present invention described herein are provided by way of example and should not be used to limit the scope of the invention to these particular embodiments. In other instances, well-known circuits, control signals, timing protocols, and software operations have not been shown in detail in order to avoid unnecessarily obscuring the invention.

FIG. 1 illustrates an apparatus 100 according to an embodiment of the invention. The apparatus 100 may comprise circuitry, one or semiconductor dice, a packaged semiconductor, a device including such circuitry, die, or package, and/or a system including such a device. The apparatus 100 may include a delay path 110, a clock generation circuit 120, and a driver circuit 115. The apparatus 100 may be included in a data path that provides input data provided to the data path input to a circuit coupled to the data path output. The delay path 110 may be coupled to the clock generation circuit 120 and the driver circuit 115, and further may be configured to receive a data signal DATA from the bus 130 and a clock signal CLK from the bus 131. The delay path 110 may include one or more logic circuits, control logic, logic gates, and/or any combination or sub-combination of the same. The clock generation circuit 120 may be configured to receive the data signal DATA and the clock signal CLK. The data signal DATA may include bits of data, and in at least one embodiment, may include write data that may correspond to a write command. The write data is provided to a circuit or circuits that are used for writing the write data to memory, for example. The clock signal CLK may be a periodic signal, and may be based, at least in part, on an external clock signal.

The clock generation circuit 120 may be any clock generator known in the art, such as a multi-phase clock generator, and may be configured to generate a plurality of clock signals based, at least in part, on the clock signal CLK. The clock generation circuit 120 may further provide the plurality of clock signals to a bus, such as the bus 140. Each of the plurality of clock signals may have a respective phase shift relative to the clock signal CLK and/or may have a same frequency as the clock signal CLK. Moreover, each of the plurality of clock signals may have a same frequency and duty cycle, or may have varying frequencies and/or duty cycles.

The driver circuit 115 may include one or more drivers and may be configured to provide (e.g., drive) one or more respective signals to a bus. For example, the driver circuit 115 may be configured to receive a data signal from bus 134, and provide the signal to a circuit, such as a memory array (not shown in FIG. 1), over bus 135. Each of the drivers included in the driver circuit 115 (not shown) may be conventional drivers as known in the art and will not be discussed in detail in the interest of brevity.

The delay path 110 may be configured to receive the data signal DATA and delay the data signal DATA based, at least in part, on the clock signal CLK and/or one or more of the plurality of clock signals from the clock generation circuit 120. As an example, the delay path 110 may sequentially shift the data signal DATA through one or more latches to delay propagation of the data signal DATA to the driver circuit 115. In at least one embodiment, this delay may be configured to match the delay resulting from the propagation of a command through a memory and/or from decoding the command (e.g., write command) This may, for example, allow the data signal DATA and corresponding decoded command signals to be provided to a circuit (not shown) at approximately the same time.

In an example operation of the apparatus 100, the clock signal CLK may be provided to the delay path 110 and the clock generation circuit 120. The clock generation circuit 120 may generate a plurality of clock signals based, at least in part, on the clock signal CLK and may provide each of the clock signals to the delay path 110 via the bus 140. The delay path 110 may further receive the data signal DATA and may delay the data signal DATA. The data signal DATA may be delayed by a particular amount or may be delayed by an amount that is adjusted dynamically, for instance, based on a temperature. The delay path 110 may delay the data signal DATA based, at least in part, on the data signal DATA and/or the plurality of clock signals from the clock generation circuit 120. As described, in one embodiment, the plurality of clock signals may be used to shift the data signal DATA through the delay path 110. The data signal DATA, once delayed, may be provided to the driver 115 over the bus 134, and thereby driven, for instance, to a circuit over the bus 135.

FIG. 2 is a block diagram of a delay path 200 according to an embodiment of the invention. The delay path 200 may be used to implement the delay path 110 of FIG. 1. The delay path includes a setup and hold unit (SUH) 202 and a delay unit 225. The SUH unit 202 may be coupled to an input of the delay unit 225, and may be configured to receive the data signal DATA and the clock signal CLK. The SUH unit 202 may further be configured to delay the data signal DATA based, at least in part, on the clock signal CLK. In at least one embodiment, delaying the data signal DATA with the SUH unit 202 may setup and hold one or more bits of the data signal DATA such that the data signal DATA may be properly delayed by the delay unit 225. For example, the SUH unit 202 may increase the amount of time in which each bit of the data signal DATA is provided to the delay unit 225. The delay unit 225 may be configured to receive the plurality of clock signals, for example, from a clock generation circuit, and may further receive the data signal DATA after it has been delayed by the SUH unit 202. The delay unit 225 may be configured to further delay the data signal DATA and provide the data signal DATA to the bus 134. The amount in which the data signal DATA is delayed by the SUH unit 202 and/or the delay unit 225 may be based, at least in part, on the amount of time required to provide and/or decode a command corresponding to the data signal DATA.

FIG. 3 is a block diagram of a delay path 300 according to an embodiment of the invention. The delay path 300 may be used to implement the delay path 110 of FIG. 1. The delay path 300 includes setup and hold (SUH) units 302 a,b, and delay units 325 a,b. The SUH unit 302 a and/or the SUH unit 302 b may be similar to the SUH unit 202 of FIG. 2 and each may be configured to receive the data signal DATA and the clock signal CLK. The SUH unit 302 a may include SUH latches 304 a,c and a skew latch 303, and the SUH unit 302 b may include SUH latches 304 b,d. Each of the SUH latches 304 a-d and the skew latch 303 may be configured to latch and/or delay received bits of a data signal. The SUH latches may be any half-latch or latch known in the art, and may be coupled in respective series configurations, as illustrated in FIG. 3. In some embodiments, the SUH latches 304 a-d and/or the skew latch 303 may be gated latches and/or may be configured to be transparent responsive to an input clock having or transitioning to a particular logic state. The delay units 325 a,b may be similar to the delay unit 225 of FIG. 2 and may be coupled to the SUH units 302 a,b, respectively. Each delay unit 325 may be configured to receive a respective set of the plurality of clock signals over the bus 140, as described in more detail below.

Each delay unit 325 may include a plurality of latches 311. For example, delay unit 325 a may include latches 311 a, 311 c, 311 e, and 311 g, and delay unit 325 b may include latches 311 b, 311 d, 311 f, and 311 h. Each latch 311 may receive a respective one of the plurality of clock signals generated by the clock generation circuit 120 and having a phase shift relative to the clock signal CLK of FIG. 1. In some embodiments, each latch 311 of the delay unit 325 a may receive one of a first respective set of the plurality of clock signals generated by the clock generation circuit 120 and each latch 311 of the delay unit 325 b may receive one of a second respective set of the plurality of clock signals generated by the clock generation circuit 120. In at least one embodiment, each respective set of the plurality of clock signals may comprise the same signals such that pairs of latches may share a same respective clock signal. For example, latches 311 a and 311 b may each be configured to receive a same clock signal over busses 140 a and 140 b, respectively, latches 311 c and 311 d may each be configured to receive a same clock signal over busses 140 c and 140 d, respectively, and so forth. In other embodiments, each latch 311 may receive its own respective clock signal from a respective bus 140. Delay units 325 may each include any number of latches 311. The latches 311 may be implemented, for example, as half-latches, D-latches, gated latches, positive edge triggered latches, negative edge triggered latches, flip-flops, and/or any other latches known by those having ordinary skill in the art, now or in the future.

Latches included in each of the delay units 325 a,b may be configured in a series configuration. For example, as illustrated in FIG. 3, an output of the latch 311 a may be coupled to an input of the latch 311 c, the output of the latch 311 c may be coupled to the input of the latch 311 e, etc. The first latch 311 of each series configuration, the latches 311 a and 311 b included in the delay units 325 a and 325 b, respectively, may be configured to receive respective bits of the data signal DATA from the SUH latches 302 a and 302 b, respectively. The last latch 311 of each series configuration, the latches 311 g and 311 h included in the delay units 325 a and 325 b, respectively, may be configured to provide respective bits of the data signal DATA to the bus 134. As will be explained, delay units 325 a and 325 b may shift respective bits of the data signal DATA through latches 311 until the entirety of the data signal DATA has been provided to the bus 134.

In an example operation of the delay path 300, the data signal DATA may be serially provided to each of the SUH units 302. As will be explained in more detail below, the first bit of the data signal DATA may be latched by the SUH unit 302 a and subsequently provided to the delay unit 325 a after a delay, and the second bit of the data signal DATA may be latched by the SUH unit 302 b and subsequently provided to the delay unit 325 b after a delay. Based, at least in part, on the respective clock signals provided to each of the latches 311, the first and second bits may be shifted through respective latches 311 of the delay units 325 a and 325 b until the first and second bits are provided to the bus 134.

In this manner, additional bits of the data signal DATA may also be latched by the SUH units 302 and shifted through the delay units 325 as well. For example, the SUH units 302 a and 302 b may alternate latching bits of the data signal DATA until all bits of the data signal DATA have been received. In one embodiment, the SUH unit 302 a and the delay unit 325 a may be configured to latch and shift even bits of the data signal DATA, and the SUH unit 302 b and the delay unit 325 b may be configured to latch and shift odd bits of the data signal DATA. As an example, delay unit 325 a may receive bits 0, 2, 4, 6, etc., and the delay unit 325 b may receive bits 1, 3, 5, 7, etc.

Moreover, the SUH unit 302 a may include a skew latch 303 coupled between the SUH latches 302 a,c. The skew latch 303 may be configured to delay the shifting of the data signal DATA through the SUH unit 302 a by a predetermined amount, such as one half of a clock cycle of the clock signal CLK. This additional delay may, for instance, align the shift of respective bits of the data signal DATA through each of the delay units 325. For example, because the first bit of the signal will arrive at the delay path 300 before the second bit, the first bit may be latched by the SUH latch 304 a before the second bit is latched by the SUH latch 304 b. Assuming that the second bit is latched by the SUH latch 304 b half of a clock cycle later, by delaying the first bit with the skew latch 303 the first and second bits may be aligned such that the bits are shifted through each delay unit 325 and/or provided to the bus 134 at approximately the same time. Subsequent bits of the data signal DATA may be adjusted in a same manner. While in one embodiment, such as the embodiment in FIG. 3, the skew latch 303 is included in the SUH unit 302 a, in other embodiments, the skew latch 303 may be elsewhere in the delay path 300. For example, in one embodiment, the skew latch may be coupled between the latch 311 g and the bus 134, thereby aligning bits of the data signal DATA before each respective bit is provided to the bus 134.

FIG. 4 is a timing diagram 400 of an example operation of the apparatus 100 of FIG. 1 according to an embodiment of the invention. The timing diagram 400 of FIG. 4 includes the data signal DATA, clock signals CLK and 440 a-d, SUH latch signals 404 a-d, skew latch signal 403, and latch signals 411 a-h. With reference to FIG. 3, the SUH latch signals 404 a-d are provided by SUH latches 304 a-d, the skew latch signal 403 are provided by the skew latch 303, and latch signals 411 a-h are provided by latches 311 a-h. As described, pairs of latches 311 may receive a same clock signal over respective busses. Thus clock signals 440 a-d are clock signals provided to latches 311 a and 311 b, 311 c and 311 d, 311 e and 311 f, and 311 g and 311 h, respectively. Moreover, reference is made herein to a data signal DATA including data bits D0, D1, D2, and D3 and delay units 325 including four latches 311, each as an example only. The operation described herein may be applicable to data signals DATA and/or delay units 325 comprising any number of bits and/or latches, respectively.

As described, the SUH latches 304 may be gated latches. Thus, in one embodiment, the SUH latch 304 a may be configured to be transparent responsive to a logic low clock signal CLK and the SUH latch 304 b may be configured to be transparent responsive to a logic high clock signal CLK. Accordingly, when the data bit D0 of the data signal DATA is be provided to SUH latches 304 a,b at a time T0, because the clock signal CLK is at a logic low, the signal 404 a provided by the SUH latch 304 a is the data bit D0, and the signal 404 b provided by the SUH latch 304 b is whatever data was previously latched when the clock signal CLK was a logic high. At time T1, the clock signal CLK may transition, for example, from a logic low to a logic high, and in response, the SUH latch 304 a may latch and the signal 404 a will continue to be DO. The signals 403 and 404 b may transition to DO based on the skew latch 303 latching and the SUH latch 304 b becoming transparent, respectively.

At time T2, the second bit of the data signal DATA, data bit D1 is provided to the SUH latches 304 a,b. Because at time T2 the SUH latch 304 a is latched, the signal 404 a remains at D0. The signal 404 b, however, may transition to D1 in response to the SUH latch 304 b becoming transparent, At time T3 the clock signal CLK transitions from a logic high to a logic low. In response, the SUH latches 304 c,d may latch, and signals 404 c,d may be D0 and D1, respectively. The transition may further cause the SUH latch 304 a to become transparent and SUH latch 304 b to latch its input. As a result, signals 404 a,b may both be data bit D1.

At time T4, a third bit of the data signal DATA, data bit D2, may be provided to the SUH latches 304 a,b. Because at time T4 the SUH latch 304 a may be transparent and the SUH latch 304 b may be latched, signal 404 a may transition to data bit D2 and signal 404 b may be held at D1. At time T5, clock signal CLK may transition to a logic high. In response, SUH latches 304 a,b may latch and become transparent, respectively, and both signals 304 a,b may comprise data bit D2. Moreover, skew latch 303 may latch based, at least in part, on the rising edge of the clock signal CLK, causing signal 403 to be data bit D2. At time T6, the clock signal 440 a may transition, for example, from a logic high to a logic low. In response to the falling edge, both the latch 311 a of the delay unit 325 a and latch 311 b of the delay unit 325 b may latch. Corresponding signals 411 a,b, as a result, may be D0 and D1, respectively.

At time T7, the fourth bit of the data signal DATA, data bit D3, may be provided. Because the SUH latch 304 a may be latched, the signal 404 a is data bit D2. The SUH latch 304 b may be transparent, and as a result, signal 404 b is data bit D3. At time T8, clock signal CLK may transition, for example, to a logic low state, As described, this may cause SUH latch 304 a to be transparent and SUH latch 304 b to latch. Signals 404 a,b therefore may both be data bit D3. Additionally, in response to the falling edge of the clock signal CLK, SUH latches 304 c,d may latch data bits D2 and D3, respectively. At time T9, the clock signal 440 b may transition, for example, to a logic low, and in response, latches 311 c,d may latch, causing signals 411 c,d to be data bits D0, D1. The data bits DO and D1 may be further shifted through respective delay units 325 at times T10 and T11, respectively, based, at least in part, on the clock signals 440 c and 440 d. As described, the final latch in each delay unit 325, for example, latches 311 g,h, may provide the data bits D0 and D1 to the bus 134. Data bits D2 and D3 may likewise be shifted based on the clock signals 440 until each is provided to the bus 134.

Accordingly, by shifting the data signal DATA through latches of both the setup and hold units 302 and the delay units 325, the data signal DATA may be delayed based on a plurality of clock signals, including the clock signal CLK and the plurality of clock signals 440. The delay may be adjusted, for example, by adjusting the number of latches or the frequency of the clock signal CLK and/or plurality of clock signals generated by the clock generation circuit 120. As described, this may, for instance, allow for the data signal DATA to be provided to a device, such as a circuit, at the same time as a corresponding memory command or decoded command signals.

FIG. 5 is a schematic diagram of a latch 500 according to an embodiment of the invention. The latch 500 may be used to implement any of the latches 311 of FIG. 3. The latch 500 may include inverters 502, 504 and a NAND gate 506. The inverters 502, 504 may be complementary metal oxide semiconductor (“CMOS”) inverters, or may be other inverters known in the art, such as n-channel or p-channel MOS inverters. The inverter 502 may be configured to receive a signal and provide a complementary signal to an input of the inverter 504. The input of the inverter 504 may further be coupled to an output of the NAND gate 506. The output of the inverter 504 may be coupled to an input of the NAND gate 506 and may comprise an output of the latch 500. The NAND gate 506 may receive a reset signal RST that may, for instance, be set to a known logic level to prevent the latch 500 from floating during an initialization of an apparatus, such as the apparatus 100. Both the inverter 502 and the NAND gate 506 may further be configured to receive a clock signal, such as one of the plurality of clock signals generated by the clock generation circuit 120 of FIG. 1, and may be selectively enabled based, at least in part, on the one of the plurality of clock signals. In at least one embodiment, the inverter 502 and the NAND 506 may be configured such that only one of the devices is selectively enabled at a given time. This may, for example, prevent both devices from providing (e.g., driving) a signal to the input of the inverter 504 simultaneously. Moreover, in some embodiments, the inverter 502 and the NAND gate 506 may be selectively enabled based a complement of the clock signal (not shown) in addition to, or instead of, the clock signal.

In an example operation of the latch 500, a bit of the data signal DATA may be provided to the inverter 502 from, for example, a latch 311 or the setup and hold latch 302 of FIG. 3. Responsive, at least in part, to the clock signal having a logic low state, the inverter 502 may be selectively enabled and the NAND gate 506 may be selectively disabled. A complement of the bit of the data signal may be provided to the inverter 504 by the inverter 502. The inverter 504 may recover the bit of the signal from its complement and provide the bit to both the NAND gate 506 and the output of the latch 500. The clock signal may transition to a logic high state, causing the inverter 504 to be selectively disabled and the NAND gate 506 to be selectively enabled. The NAND gate 506 and the inverter 504 may hold the bit for the duration of the time that the clock signal remains in a logic low state, providing the bit of the signal at the output of the latch 500 during that period of time.

FIG. 6 illustrates a block diagram of a portion of a memory 600 according to an embodiment of the invention. The memory 600 includes an array 602 of memory cells, which may be, for example, DRAM memory cells, SRAM memory cells, flash memory cells, or some other types of memory cells. The memory 600 includes an address/command decoder 606 that receives memory commands and addresses through an ADDR/CMD bus. The address/command decoder 606 generates control signals, based on the commands received through the ADDR/CMD bus. The address/command decoder 606 also provides row and column addresses to the memory 600 through an address bus and an address latch 610. The address latch then outputs separate column addresses and separate row addresses.

The row and column addresses are provided by the address latch 610 to a row address decoder 622 and a column address decoder 628, respectively. The column address decoder 628 selects lines extending through the array 602 corresponding to respective column addresses. The row address decoder 622 is connected to word line driver 624 that activates respective rows of memory cells in the array 602 corresponding to received row addresses. The selected line (e.g., a bit line or bit lines) corresponding to a received column address are coupled to a read/write circuitry 630 to provide read data to a data output circuit 634 via an input-output data bus 640. Write data are provided to the memory array 602 through a data path 650 of the data input circuit 644 and the memory array read/write circuitry 630. The data path 650 may comprise an apparatus according to an embodiment of the invention, such as the apparatus 100, and may delay write data as described herein.

At least a portion of the data output circuit 634 may include an apparatus 640 that includes an encoding circuit and driver circuit, such as those previously described with reference to the apparatus 100 according to an embodiment of the invention. In addition to, or in place of, the apparatus 640 of the data output circuit 634, an apparatus 640 may also be included on input-output data bus 640, in between the memory array 602 and the read/write circuitry 630, or in any other location in the memory 600.

From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims. 

What is claimed is:
 1. An apparatus, comprising: a clock generation circuit configured to receive an input clock signal and generate a plurality of clock signals based, at least in part, on the input clock signal; a delay path coupled to the clock generation circuit and configured to receive the input clock signal and the plurality of clock signals, the delay path further configured to receive a data signal and delay the data signal based, at least in part, on the input clock signal and each of the plurality of clock signals; and a driver coupled to the delay path and configured to receive the delayed data signal, the driver further configured to provide the delayed data signal to a bus.
 2. The apparatus of claim 1, wherein the data signal comprises a write data signal and the bus is coupled to a memory array.
 3. The apparatus of claim 1, wherein the delay path comprises a plurality of latches, each latch configured to receive one of the plurality of clock signals.
 4. The apparatus of claim 3, wherein the plurality of latches are coupled in series.
 5. The apparatus of claim 3, wherein each of the latches comprises: a first inverter configured to drive an output; a second inverter coupled to an input of the first inverter and configured to receive a data signal, the second inverter further configured to provide a first input signal to the input of the first inverter based, at least in part, on the data signal; a NAND gate coupled to the output and the input of the first inverter, the NAND gate further configured to provide a second input signal to the input of the first inverter based, at least in part, on the output; and wherein at least one of the second inverter or the NAND gate are configured to be selectively enabled based, at least in part, on one of the plurality of clock signals.
 6. The apparatus of claim 1, wherein the delay path comprises: a setup and hold unit configured to receive the data signal and the input clock signal and delay the data signal by a first delay based, at least in part, on the input clock signal; and a delay unit coupled to the setup and hold unit and configured to receive the data signal after the first delay and the plurality of clock signals, the delay unit further configured to delay the data signal by a second delay based, at least in part, on the plurality of clock signals.
 7. The apparatus of claim 6, wherein the second delay comprises a plurality of delays, each of the plurality of delays based, at least in part, on a respective one of the plurality of clock signals.
 8. The apparatus of claim 1, wherein the delay path is further configured to delay the data signal based, at least in part, on the delay of a write command.
 9. An apparatus comprising: a clock generation circuit configured to receive an input clock signal and generate a plurality of clock signals based, at least in part, on the input clock signal; and a delay path coupled to the clock generation circuit, comprising: a first setup and hold unit configured to receive the data signal and latch a first bit of a data signal; a second setup and hold unit configured to receive the data signal and latch a second bit of the data signal; a first delay unit coupled to the first setup and hold unit and configured to receive the first bit of the data signal, the first delay unit further configured to delay the first bit of the data signal using a first plurality of latches; a second delay unit coupled to the second setup and hold unit and configured to receive the second bit of the data signal, the second delay unit further configured to delay the second bit of the data signal using a second plurality of latches; and wherein each of the first plurality of latches is configured to delay the first bit of the data signal based, at least in part, on a respective one of a first set of the plurality of clock signals and each of the second plurality of latches is configured to delay the second bit of the data signal based, at least in part, on a respective one of a second set of the plurality of clock signals.
 10. The apparatus of claim 9, wherein the first setup and hold unit comprises a skew latch configured to delay the first bit of the data signal one-half of a clock cycle of the input clock signal.
 11. The apparatus of claim 9, wherein the first and second sets of the plurality of clock signals comprise a same plurality of clock signals.
 12. The apparatus of claim 9, further comprising: a driver circuit coupled to the first and second delay units and configured to receive the first and second bits of the data signal, the driver circuit further configured to provide the first and second bits of the data signal to a memory array.
 13. The apparatus of claim 9, wherein the first setup and hold unit is configured to latch the first bit based, at least in part, on the input clock signal and the second setup and hold unit is configured to latch the second bit based, at least in part, on the input clock signal.
 14. The apparatus of claim 13, wherein the first setup and hold unit is further configured to latch the first bit responsive, at least in part, to receipt of a rising edge of the input clock signal and the second setup and hold unit is further configured to latch the second bit responsive, at least in part, to receipt of a falling edge of the input clock signal.
 15. The apparatus of claim 9, wherein the apparatus is included in a memory.
 16. A method, comprising: generating a plurality of clock signals based on an input clock signal; delaying a first bit of a data signal a first amount; delaying a second bit of the data signal a second amount; and delaying the first and second bits of the data signal by a third amount based, at least in part, on the plurality of clock signals; wherein the first and second amounts are based, at least in part, on the input clock signal.
 17. The method of claim 16, wherein said delaying a first bit of a data signal a first amount, comprises: delaying the first bit one-half of a clock cycle of the input clock signal.
 18. The method of claim 16, further comprising: providing the first and second bits to a bus at approximately the same time.
 19. The method of claim 16, wherein said delaying the first and second bits comprises: shifting the first bit through a first plurality of latches; and shifting the second bit through a second plurality of latches.
 20. A method, comprising: latching a first data bit with a first setup and hold unit; after latching the first data bit, latching a second data bit with a second setup and hold unit; and shifting the first data bit through a first plurality of latches based, at least in part, on a first plurality of clock signals; shifting a second data bit through a second plurality of latches based, at least in part, on a second plurality of clock signals; and wherein the first and second pluralities of latches are configured in series.
 21. The method of claim 20, wherein each of the first plurality of latches is configured to delay the first data bit based, at least in part, on a respective one of the first plurality of clock signals and each of the second plurality of latches is configured to delay the second data bit based, at least in part, on a respective one of the second plurality of clock signals.
 22. The method of claim 20, wherein each of the first and second pluralities of latches are configured to latch responsive, at least in part, to receipt of a falling edge of a signal.
 23. The method of claim 20, further comprising: providing the first and second bits to a bus at approximately the same time.
 24. The method of claim 20, wherein the first and second pluralities of clock signals comprise the same clock signals. 